Industry
Probook
- Chief Architect
Intelligent Systems
Agentic workflows, real-time speech, infrastructure, and reliable execution.
New York · Building at Probook
AI systems · Education · Engineering leadership
Christian Yongwhan Lim
Building AI systems, technical organizations, and the next generation of engineers.
- Chief Architect · Probook
- Adjunct, Computer Science · Columbia University
- Director of Internships · ICPC Foundation
- Formerly Google Research & Two Sigma
639+
Research citations
428+
Columbia competitive programming members
107
ICPC internships completed
17
Universities — invited talks
14×
Courses taught at Columbia
2×
ICPC World Finals teams coached
Mission
I build systems that help people solve hard problems at scale.
Throughout my career, I’ve been driven by a simple belief: exceptional people, equipped with the right tools, communities, and opportunities, can accomplish extraordinary things. Whether through AI, education, infrastructure, or competitive programming, I enjoy building systems and organizations where talent can grow, collaborate, and compound over time.
Today, I serve as Chief Architect at Probook, where I help build AI-native systems that transform how home service businesses operate. Previously, I worked at Google Research and Two Sigma, developing infrastructure and platforms that enabled large-scale research, machine learning, and decision-making.
Beyond industry, I’ve spent more than a decade investing in technical talent development. I teach Computer Science at Columbia University, serve as Director of Internships at the ICPC Foundation, coach ICPC and IOI teams worldwide, and help organize international programming competitions, training camps, and educational initiatives.
If you’re building ambitious products, advancing AI, strengthening technical communities, or investing in the next generation of builders and researchers, I’d be happy to connect.
Current Focus
- AI voice agents
- Real-time speech & LLM systems
- Engineering leadership
- ICPC education & curriculum
- Mentorship
- The Journal of Competitive Learning
Impact at a Glance
Compounding reach
Research, education, and community — built to reinforce one another.
Each area is a different expression of the same work: creating reliable systems, widening access to opportunity, and helping technical talent grow.
How the Work Connects
Core principle
Build systems that help people solve hard problems.
Education
Curriculum, deliberate practice, teaching, and technical talent development.
Community
Competitions, camps, mentorship networks, and institutions that compound.
Selected Impact
Industry
Community
AI-Native Systems
Chief Architect at Probook — real-time speech, LLMs, and infrastructure powering AI voice agents for home service businesses. Previously large-scale research and ML platforms at Google Research and Two Sigma.
Competitive Programming
Columbia coach with two ICPC World Finals appearances; Director of Internships and Symposium Chair at the ICPC Foundation; Chief Judge, curriculum co-chair, and IOI trainer.
ICPC leadership → EducationTeaching & Mentorship
Fourteen course offerings at Columbia through Fall 2026 across competitive programming and interview preparation, plus a decade of mentoring engineers, researchers, and students worldwide.
Courses & mentorship → ResearchResearch
Peer-reviewed work spanning computer vision, social networks, programming languages, and competitive learning — 639+ citations, from CVPR and IJCV to OOPSLA.
Publications →Current Appointments & Leadership
ICPC
International Collegiate Programming Contest
- Director of Internships, ICPC Foundation
- Chair, ICPC CLI Symposium
- Senior Editor, The Journal of Competitive Learning
- Chief Judge, ICPC North America Mid-Central
- Co-Chair, Curriculum Committee
- Co-Organizer, ICPC North America Programming Camp — Online
- Site Director, ICPC North America Greater New York Regional
- Coach, Columbia University
IOI
International Olympiad in Informatics
- Trainer, Team Pakistan
Academia
Columbia University
- Adjunct, Department of Computer Science
Alumni leadership
Stanford University
- Co-Chair, Class of 2011 15th Reunion Campaign
- Co-Chair, Attendance and Outreach, Stanford Reunion Homecoming
- Board of Directors, Asian Pacific American Alumni Club — Co-President (2026–); Chair, Advocacy and Education Committee (2025–2026)
Trajectory
-
Present
Chief Architect — Probook
AI-native systems for home service businesses: real-time speech, LLMs, and the infrastructure behind them.
-
2025 — Present
Director of Internships — ICPC Foundation
Leading the global internship program: 107 completions and 19+ active interns across archive, journal, systems, and training projects. Program manager since 2022.
-
2022 — Present
Adjunct & ICPC Coach — Columbia University
Fourteen course offerings through Fall 2026; coached Columbia teams to the 2022 and 2024 ICPC World Finals.
-
2022 — 2023
Senior Quantitative Software Engineer — Two Sigma
Quantitative platforms and large-scale decision-making infrastructure.
-
2016 — 2022
Research Software Engineer — Google Research
Infrastructure and platforms enabling large-scale research and machine learning.
-
2013 — 2016
PhD Studies — MIT
Advised by Asuman Ozdaglar; research on networks and cascades. On leave since 2016.
-
2007 — 2013
BS & MS — Stanford University
BS ’11 in Mathematics and Computer Science (double major); MS ’13 in Computer Science. Advised by Fei-Fei Li (CS) and Persi Diaconis (Math).
Selected Awards
Nov 2025
Outstanding Problem Advisory — Taking the Field Medal
Nov 2025 & Oct 2024
Outstanding Mentorship Award — Quatrefoil Medal
May 2024
Silver Medal (3rd Place) — Team Coach
May 2023
Excellence in Leadership Award
Education
2013 — 2016
Massachusetts Institute of Technology
2007 — 2013